Molecular diagnostics in the treatment of leukemia

The molecular characterization of childhood leukemias directly affects our treatment strategies. Acute lymphoblastic leukemia patients with the TEL-AML1 fusion have a favorable prognosis, whereas those with the E2A-PBX1 fusion require more intensive therapy to obtain a good outcome. Acute lymphoblastic leukemia patients whose leukemic lymphoblasts contain the MLL-AF4 or the BCR-ABL fusion are often candidates for allogeneic hematopoietic stem cell transplantation during first remission. Among acute myeloid leukemia patients, AML1-ETO and CBFbeta-MYH11 fusions are associated with a favorable response, especially when the chemotherapy regimen includes high-dose cytarabine. Patients with acute promyelocytic leukemia who carry the PML-RAR alpha fusion respond to all-trans retinoic acid and have an excellent outcome after treatment with all-trans retinoic acid in combination with anthracyclines. Several novel therapeutic agents targeted to molecular lesions of leukemic cells are under investigation.